If it has no barrel, then the 38/55 is a great choice.
Several years back, when I learned that the Winchester brass was a bit short and the long Starline brass was avaliable, I bought all the long brass that Double Tap Sports had, about 700 pieces. Over the years , I used it and sold some to my friends. Over the years, the 38/55's came and went.
Now, my main shooters are a Ruger #1 and #3, both with heavy barrels. One is a Ron Smith barrel from the eighties and the other may be as well.
Last year, thinking that I had a nice snug chamber, I noticed that the cartridge was being crimped on clambering.
Apparently, Mr. Smith made a reamer for the short chamber rather than using SAAMI specs. This was perfectly logical for a custom rifle to have a chamber that was tailored for the cases and ammunition available at that time.
It's somewhat ironic that I'll be trimming some of my long 38/55 brass to match the length of the Winchester brass.
So, if the OP decides to go with the 38/55, he's facing the decision of what chamber length to choose.
A chum several towns away, is making barrels, and I have a nice barreled long Lee that was converted to a lamp, and I think that it would make a nice 38/55 target rifle.